The exemplary embodiments are directed to an electrostatic image transfer apparatus. More specifically, the exemplary embodiments are directed to an apparatus, a method and a system for feedforward of sheet electrostatic tacking parameters to an image transfer assembly.
Electrostatic imaging and printing processes are comprised of several distinct stages. These stages may generally be described as (1) charging, (2) imaging, (3) exposing, (4) developing, (5) transferring, (6) fusing and (7) cleaning. In the charging stage, uniform electrical charges are deposited on a charge retentive surface, such as, for example, a surface of a photoreceptor, so as to electrostatically sensitize the surface. Imaging converts an original, or digital image into a projected image on the surface of the photoreceptor and the image is then exposed upon the sensitized photoreceptor surface. An electrostatic latent image is thus recorded on the photoreceptor surface corresponding to the original, or digital image.
Development of the electrostatic latent image occurs when charged toner particles are brought into contact with this electrostatic latent image. The charged toner particles are attracted to either the charged or discharged regions of the photoreceptor surface that correspond to the electrostatic latent image, depending on whether a charged area development (CAD) or a discharged area development (DAD, more common) is being employed.
In the case of a single step transfer process, the photoreceptor surface with the electrostatically attracted toner particles is then brought into contact with an image receiving surface, i.e., paper or other similar substrate; Toner particles are imparted to the image receiving surface by a transferring process wherein an electrostatic field attracts the toner particles toward the image receiving surface, causing the toner particles to adhere to the image receiving surface rather than to the photoreceptor. Toner particles then fuse into the image receiving surface by a process of melting and/or pressing. The process is completed when the remaining toner particles are removed or cleaned from the photoreceptor surface.
An objective of the transferring process is to ensure that all of the toner is removed from the photoreceptor surface onto the paper or other suitable media. To accomplish this objective, it is known in the art that an electric field, or transfer field, is built at the point at which the media passes the photoreceptor for transfer as it is carried by a belt through the image transfer apparatus. As the media enters the transfer nip, a roll that may be electrically biased applies pressure to the media in a direction opposite of pressure applied by the photoreceptor to the media to enhance toner transfer to the media. The transfer field assists in applying a net force on the toner particles that causes the toner particles to move from the photoreceptor to the paper.